Triflow muffler for exhaust gases



March 3, 1970 A. HEATH I TRIFLOW MUFFLER FOR EXHAUST GASES Filed Sept. 26, 1967 J 1 J J J J 1 J J 1 3 3 .3

United States Patent 3,498,406 TRIFLOW MUFFLER FOR EXHAUST GASES Robert A. Heath, Jackson, Mich., assignor to Walker Manufacturing Company, Racine, Wis., a corporation of Delaware Filed Sept. 26, 1967, Ser. No. 670,577 Int. Cl. F01n 1/10 US. Cl. 18153 Claims ABSTRACT OF THE DISCLOSURE A very small diameter and simple mufller construction has aligned inlet and outlet tubes with means to block straight-through communication between them so that gas flows transversely from the inlet point and then longitudinally through the mufller outside of the tubes and then transversely into the outlet tube.

Brief summary of the invention The lack of available space beneath modern automobiles for mufllers has prompted a search for small silencing components which, for their size, are highly eflicient in extracting sound energy from gas flowing through them. The present invention provides such a small muffler by means of a very small unit having aligned inlet and outlet pipes which are prevented by a barrier from directly communicating with each other. Gas therefore flows radially and longitudinally through the mufller casing in what may be described generally as a tri-flow pattern.

Description of the drawings FIGURE 1 is a longitudinal cross-section through one form of muffler embodying the invention; and

FIGURE 2 is a longitudinal cross-section through a second embodiment of the invention.

Description of the invention The mufller 1 of FIGURE 1 comprises three parts. \First, there is an outer shell 3 which is reduced in diameter at opposite ends 5 and 7 to form bushings for attachment to exhaust and tailpipes in an exhaust system. Second, there is an internal gas flow tube 9 which has opposite ends nested in recesses 11 and 13 formed in the bushings 5 and 7. This fitting may be done during assembly and eliminates the need for spot welding the tube 9 to the shell as can be seen. Third, there is partition 15 having a flange that is welded to the shell 3 and a neck 17 which may or may not be welded to the tube 9.

The tube 9 is pinched together at 19 to divide it into an inlet section 21 and an outlet section 23 which are out of direct communication with each other by virtue of the imperforate barrier 25 provided by the necked or pinched section 19. The inlet section 21 is provided with a bank of louvers or openings 27 through which gas can flow from tube 21 into the chamber 29 that is defined by the partition 15 and the inlet end of the shell 3. Within the chamber 29 the outlet section 23 has several large openings 31 through which gas can flow into the outlet section and then out of the mufller through bushing 7. The space between the partition and the end of the shell 3 comprises a closed chamber 33 and the louvers 35 connect the gas in the tube 23 to this chamber so that relatively high frequency sounds in the gas are attenuated thereby.

3,498,406 Patented Mar. 3, 1970 ice In operation of the mufller 1, gas entering the mufller bushing 5 is forced by partition 15 to flow radially through the louvers 27 into the chamber 29. Silencing occurs as the gas flows through the short necks of the louvers 27 and as it expands into the relatively large volume of chamber 29. The gas in chamber 29 flows longitudinally towards partition 15 which forces it radially into the reduced diameter openings 31 where silencing occurs as it does again when the gas expands inside of the outlet section 23. High frequency noises, roughness, and spit are attenuated by the action of louvers 35 in conjunction with the closed chamber 33 as the gas flows down through the tube 9.

In the mufller 41 of FIGURE 2, there is an outer shell 43 which is necked down in an inlet bushing 45 which supports an inlet tube 47. It is necked down in an outlet bushing 49 which receives and supports the reduced diameter end 51 of an outlet tube 53 which is larger in diameter and telescopes over the down-stream end of the inlet tube 47. Imperforate partition 55 in tube 53 blocks direct communication between the tube 47 and the interior of the tube 53 downstream of the partition 55. The co-extensive sections of the tubes 47 and 53 are louvered as seen at 57 and 59 and the portion of the outlet tube 53 located downstream of the partition 55 is louvered as seen at 61.

Gas entering the inlet tube 47 is forced by the partition 55 to reverse its flow and pass backwardly through the annular chamber 63 between the co-extensive portions of the inlet and outlet tubes. Some cross-flow occurs through the louvers 57 and 59 to minimize back pressure and these louvers also act to attenute high frequency noises. The gas leaves chamber 63 near the front of the mufller and reverses its flow so that it is again directed toward the outlet end of the mufller as it enters the annular chamber 65 between the outlet tube 51 and the shell 43. It then enters the interior of the tube 51 by passing through the louvers 61 where silencing occurs.

In both forms of the invention the outer shell 3 or 43 can be made very small in diameter (for example 3" to 4") thus enabling the device to be fitted into positions underneath an automobile that would not accept a normal muffler.

Modifications may be made in the structure shown without departing from the spirit and scope of the invention.

What is claimed is:

1. A triflow type mufller for silencing sound in flowing gases comprising a small diameter shell, substantially aligned inlet and outlet tubes in the shell, the space between said tubes and shell forming a longitudinally extending chamber, transverse partition means blocking direct gas flow from the inlet to the outlet tube, said inlet tube having an outlet opening located on one side of the partition means and said outlet tube having an inlet opening located on the opposite side of said partition means, both said openings communicating with said chamber and gas flowing from one to the other through said chamber, said outlet tube being telescoped over the inlet tube and said partition means being provided in said outlet tube, overlapping sections of said telescoped tubes each having louver patches therein.

2. A triflow type mufliervfor silencing sound in flowing gas comprising a small diameter shell having an inlet opening at one end and an outlet opening at the other end, said openings being substantially aligned, an inlet tube open at both ends and mounted in said inlet opening, an outlet tube open at both ends and mounted in said outlet opening, said tubes being substantially coaxial and one of said tubes :being larger in diameter than the'other and having a transverse partition in it located at an intermediate point along its length and blocking flow through it, said larger tube having perforations in the wall thereof located between said partition and the end of the tube which is mounted in said shell opening, the smaller of said tubes extending inside the larger tube and terminating a spaced axial distance from said partition, the space between said tubes and said shell providing a longitudinally extending chamber into which said perforations open, the space inside the larger tube between the overlapped portions of said tubes comprising a longitudinal passage opening into said chamber and providing a path for flow of gas between the smaller tube and the chamber.

3. A mufiier as set forth in claim 2 wherein the Wall of at least one of the tubes in the sections thereof forming said longitudinal passage is perforated.

4. A muffler as set forth in claim 3 wherein the walls of both tubes in the sections thereof forming said longitudinal passage are perforated.

5. A mufiler as set forth in claim 4 wherein all of said perforations are in the form of-louver patches.-

References Cited UNITED STATES PATENTS 1,051,130 1/1913 Lattime 18l-53 XR 1,131,233 3/1915 Gorosa 18l--53 1,338,520 4/1920 Moores 18153 XR 1,553,264 9/1925 Reasonover l8153 XR 2,109,220 2/1938 Noblitt et a1. 181-54 2,675,088 4/1954 McLeod. 3,036,655 5/1962 Powers 18l54 FOREIGN PATENTS 5/1927 France.

ROBERT S. WARD, 111., Primary Examiner US. Cl. X.R. 

